She appeared to pay a subtle tribute to her 92-year-old grandmother with her choice of outfit for the annual event.

Eugenie, 29, wore Erdem’s floral-print silk crepe de chine ‘Bernette’ dress, which was inspired by Her Majesty’s style in the 1950s.

While the £831 frock is now sold out, according to Net-a-Porter, the Canadian-born designer delved “deep into Queen Elizabeth II's past for his Spring '18 collection” and was “particularly drawn to her style in the '50s.”